Methods for processing sensor signals for systems for use by robots to detect surroundings have been known for a long time from the field of computer science and robotics. According to these methods, a sensor detection range of interest is subdivided into a specified number of fields. A probability value is determined for each field, as a measure of the presence of an obstacle in the particular field. These methods are referred to as “occupancy grids”, “belief grids”, or “evidence grids”. Accordingly, procedures of this type form a potential basis for grid-based sensor signal processing and sensor data fusion.
It is provided in DE 10 2004 007 553 A1 that a motor vehicle's surroundings be subdivided into discrete fields to enable a motor vehicle safety system to detect its surroundings. The probability value of each field is compared with a specified probability threshold value. If the probability value of the field is greater than the specified probability threshold value, it is possible to deduce the presence of an obstacle in this field and, therefore, in the vehicle's surroundings.
A grid-based method of object detection is made known in DE 10 2004 032 118 A1. In that case, a vehicle's surroundings are detected by a sensor in a cyclic manner. Values measured by the sensor are projected into a freely specifiable grid, and they are combined to form grid-based segments which may be allocated to known objects. Moreover, “tracks” for these objects are determined, which may be used to control motor vehicle functions. In this method, it is provided that the increments of the cells in the grid differ and are shaped in the radial and/or circumferential direction in a manner such that an object resolution may be obtained that is optimized in terms of functionality.
DE 10 2004 039 095 A1 describes a system for detecting pedestrians using a sensor for detecting the surroundings. The sensor data are allocated to one another in a grid using the “grid of evidence” method.
The processing and fusion of data obtained via sensors for the reliable detection of objects using a grid-based method is known from EP 1 672 390 A1. It is provided, e.g., that first data are provided by a radar sensor, and second data are provided by a lidar sensor.